1. Field of the Invention
The present invention relates to emergency breathing systems including user-donnable breathing hoods for supplying breathing oxygen to a user as for escape from an aircraft, and, more specifically, to a control valve for such a system for selectively switching from normal breathing oxygen such as the aircraft oxygen supply to a pressurized emergency source of breathing oxygen.
2. Known Art
Oxygen supply devices are desirable for emergency situation, particularly by crew or passengers in aircraft. More specifically, oxygen supply devices that not only supply breathing oxygen from a plumbed source such as the drop-down “DIXIE” cup construction disclosed in Jumpertz U.S. Pat. No. 5,301,665. An advance in the art relating to these devices is disclosed in Bower et al. U.S. Pat. No. 6,247,471 which is incorporated in its entirety by reference.
In aircraft, emergency oxygen supply devices employing the presently inventive apparatus are to be tightly bundled to fit within a compartment above the seats of aircraft passengers. Upon encountering a situation such as a reduced cabin pressure condition, a door to the compartment opens and the oxygen supply device drops down and dangles by a flexible hose which is connected to a plumbed breathing oxygen source in the aircraft. The seated aircraft passenger then dons a breathing hood which is included with the device to begin receiving oxygen from the plumbed oxygen source. The passengers continue to receive oxygen in this fashion until instructed by a crewmember to pull a lanyard that is connected to the device which not only disconnects the passenger from the plumbed oxygen source but activates a portable emergency oxygen source. This oxygen source is a 3,000 psi bottle of compact construction which inflates the breathing hood with an oxygen mixture to provide the aircraft passenger with enough breathing oxygen to leave his seat and escape from the aircraft.
The present invention relates to an improvement to the control valve in an oxygen supply device which operates with fewer moving parts for high reliability, manufacturability, and compactness.